There are two kinds of water: salt water and fresh water. Salt water contains large quantities of salt, while fresh water has a dissolved salt concentration of less than 1%. Only fresh water can be used as drinking water. Water is the only substance on earth that is found naturally
Oxygen gas is colorless, odorless, and tasteless.It’s usually purified by fractional distillation of liquefied air, but the element is found in many compounds, such as water, silica, and carbon dioxide. Oxygen was the atomic weight standard for the other elements until 1961 when it was replaced by carbon 12. Oxygen made a good choice for […]